Astronomy Colloquium for 2021-12-01

Series: Astronomy Colloquium
Date: Wednesday 01-Dec-2021
Time: 16:05-17:00 (4:05-5:00 pm)
Location: Via Zoom
Speaker: Dr. Peter Gao (Carnegie Institute for Science)
Title: Lifting the Veil on Exoplanet Clouds and Hazes

Clouds and hazes are common in the atmospheres of exoplanets across a wide swath of temperatures, masses, and ages. These aerosols strongly impact observations of transmitted, reflected,and emitted light from exoplanets, obfuscating our understanding of exoplanet thermal structure and composition. In this talk, I will discuss how aerosol microphysics modeling has helped advance our understanding of exoplanet aerosols and atmospheres. By constraining an aerosol microphysics model with trends in exoplanet transmission spectra, we found that silicates dominate aerosol opacity above planetary equilibrium temperatures of 950 K due to low nucleation energy barriers and high elemental abundances, while hydrocarbon hazes dominate below 950 K due to a rapid increase in methane abundance and photodissociation rate. In addition, spatial heterogeneity of exoplanet clouds can explain the observed homogeneity in the nightside temperatures of hot Jupiters, while also leading to asymmetry between the dawn and dusk limbs of exoplanets in transits. Meanwhile, high altitude photochemical hazes may strongly impact our understanding of mini-Neptune mass-radius relationships. I will conclude by describing how we can further characterize exoplanet clouds and hazes in the years to come.

Colloquia for the Fall 2020 semester will be held on zoom. Contact Dr. Leslie Sage for details.

Colloquium Organizer: Dr. Leslie Sage


Special accommodations for individuals with disabilities can be made by calling (301) 405-3001. It would be appreciated if we are notified at least one week in advance.


Directions and information about parking can be found here.

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